well established Skimmia popping its clogs

Hi my long-lived and reliable skimmia has suddenly, over only 2 days, almost died - yellowing leaves and it is in a real state. Such a shock to see it. I am wondering if it is drought as we have had no rain for a while down south. If so, will it recover? However what worries me is that it was next to a large well-established euonymus which last year also succumbed very suddenly to scale - almost gone in about four days flat and I had to take it out. I don't think I have any chance of saving this skimmia, but to lose two large shrubs adjacent to one another so quickly is worrying. I am going to have to replant something but should I be checking for some kind of virus, or grub? I attach a photo - it is dying from the exposed side where the old shrub was, towards the still green side ..... Helllllppp!!!

 

It is odd that it is dying from the fence side, the rest of the bush looks as if it was doing really well, plenty of foliage and flowers.
Is there any chance your neighbour has sprayed their side of the fence, or watered using something for pest or weed control? Can you have a look over the fence into their garden to see what is happening on their side? The answer may be coming from them.
I would leave well alone for a few months to see if the whole bush dies. If it does, or if any more of your plants die I would wait a year or two before trying to replant. I doubt if aphids etc. are the cause, they would be all over the plant, not just on one side.

 

Is there a broken or partially broken branch somewhere near the base?

 

Sadly no, it looks completely sound branch wise. I am checking with the neighbour to see if anythings gone on there. Thanks for the thought

 

Is that dead ivy on the fence in the first picture? If it is and you haven't deliberately killed it, then something might be going on in your neighbours garden.

 

Good spot! Anything that's been sprayed on that ivy could easily have drifted onto the skimmia.